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appliancedestroyer · Apprentice DIYer Joined: 17 Feb 2009 Posts: 2

Panasonic NN-T994SFR Never a problem until last night while heating up some food it started shooting smoke out of the bottom. What to do next? Trying to take it apart but it has those torx screws with a circle in the middle. Not sure what those are called and right now don't have a bit to fit them. It's only 3 years old and would like to at least try to fix it before pitching it.

Virtual Repairman · Posted: Sun Mar 22, 2009 5:28 am Post subject: micro

Those are security Torx screws, mainly to keep people like you out of the dangerous parts of the unit. Have you ever worked on a microwave before...do you know what's in there?
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appliancedestroyer · Apprentice DIYer Joined: 17 Feb 2009 Posts: 2

Never been inside the back of a microwave. I guess I was just going to look for the obvious melted wiring or something grounded out. I read the words dangerous, I will wait to read the reply before going further.

Virtual Repairman · Posted: Sun Mar 22, 2009 9:08 am Post subject: back there

What's inside there is a high and a low voltage section. Smoke usually comes from a bad magnetron tube which causes the transformer to overheat. There's also a capacitor and a high-voltage diode in line with the mag tube which can burn out as well. All this stuff has about 15, 000 volts going to it, so this is why it is considered dangerous to mess around back there if you are not familiar.

I usually check the mag tube terminals with my OHM meter, looking for about 1 OHM resistance. Also check each terminal on the mag tub to the metal cover to check for shorts. You pretty much have to be an electronics guy to test the diode and capcitor, which is why there are limited things someone with no experience can do.
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